Correct the fallbacks for mailer configuration (#21945)

Unfortunately the fallback configuration code for [mailer] that were
added in #18982 are incorrect. When you read a value from an ini section
that key is added. This leads to a failure of the fallback mechanism.
Further there is also a spelling mistake in the startTLS configuration.

This PR restructures the mailer code to first map the deprecated
settings on to the new ones - and then use ini.MapTo to map those on to
the struct with additional validation as necessary.

Ref #21744

Signed-off-by: Andrew Thornton <art27@cantab.net>

5 files changed, 96 insertions, 94 deletions

diff --git a/custom/conf/app.example.ini b/custom/conf/app.example.ini
index e7ddda4b8a..5822dc1e4a 100644
--- a/custom/conf/app.example.ini
+++ b/custom/conf/app.example.ini
@@ -1590,7 +1590,7 @@ ROUTER = console
 ;; Prefix displayed before subject in mail
 ;SUBJECT_PREFIX =
 ;;
-;; Mail server protocol. One of "smtp", "smtps", "smtp+startls", "smtp+unix", "sendmail", "dummy".
+;; Mail server protocol. One of "smtp", "smtps", "smtp+starttls", "smtp+unix", "sendmail", "dummy".
 ;; - sendmail: use the operating system's `sendmail` command instead of SMTP. This is common on Linux systems.
 ;; - dummy: send email messages to the log as a testing phase.
 ;; If your provider does not explicitly say which protocol it uses but does provide a port,
diff --git a/docs/content/doc/advanced/config-cheat-sheet.en-us.md b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
index 468c6d5edc..853f0c67f2 100644
--- a/docs/content/doc/advanced/config-cheat-sheet.en-us.md
+++ b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
@@ -713,7 +713,7 @@ and
 [Gitea 1.17 configuration document](https://github.com/go-gitea/gitea/blob/release/v1.17/docs/content/doc/advanced/config-cheat-sheet.en-us.md)
 
 - `ENABLED`: **false**: Enable to use a mail service.
-- `PROTOCOL`: **\<empty\>**: Mail server protocol. One of "smtp", "smtps", "smtp+startls", "smtp+unix", "sendmail", "dummy". _Before 1.18, this was inferred from a combination of `MAILER_TYPE` and `IS_TLS_ENABLED`._
+- `PROTOCOL`: **\<empty\>**: Mail server protocol. One of "smtp", "smtps", "smtp+starttls", "smtp+unix", "sendmail", "dummy". _Before 1.18, this was inferred from a combination of `MAILER_TYPE` and `IS_TLS_ENABLED`._
   - SMTP family, if your provider does not explicitly say which protocol it uses but does provide a port, you can set SMTP_PORT instead and this will be inferred.
   - **sendmail** Use the operating system's `sendmail` command instead of SMTP. This is common on Linux systems.
   - **dummy** Send email messages to the log as a testing phase.
diff --git a/modules/setting/mailer.go b/modules/setting/mailer.go
index d6f1dae0f7..5a9b7054b9 100644
--- a/modules/setting/mailer.go
+++ b/modules/setting/mailer.go
@@ -18,32 +18,33 @@ import (
 // Mailer represents mail service.
 type Mailer struct {
 	// Mailer
-	Name                 string
-	From                 string
-	EnvelopeFrom         string
-	OverrideEnvelopeFrom bool `ini:"-"`
-	FromName             string
-	FromEmail            string
-	SendAsPlainText      bool
-	SubjectPrefix        string
+	Name                 string `ini:"NAME"`
+	From                 string `ini:"FROM"`
+	EnvelopeFrom         string `ini:"ENVELOPE_FROM"`
+	OverrideEnvelopeFrom bool   `ini:"-"`
+	FromName             string `ini:"-"`
+	FromEmail            string `ini:"-"`
+	SendAsPlainText      bool   `ini:"SEND_AS_PLAIN_TEXT"`
+	SubjectPrefix        string `ini:"SUBJECT_PREFIX"`
 
 	// SMTP sender
-	Protocol             string
-	SMTPAddr             string
-	SMTPPort             string
-	User, Passwd         string
-	EnableHelo           bool
-	HeloHostname         string
-	ForceTrustServerCert bool
-	UseClientCert        bool
-	ClientCertFile       string
-	ClientKeyFile        string
+	Protocol             string `ini:"PROTOCOL"`
+	SMTPAddr             string `ini:"SMTP_ADDR"`
+	SMTPPort             string `ini:"SMTP_PORT"`
+	User                 string `ini:"USER"`
+	Passwd               string `ini:"PASSWD"`
+	EnableHelo           bool   `ini:"ENABLE_HELO"`
+	HeloHostname         string `ini:"HELO_HOSTNAME"`
+	ForceTrustServerCert bool   `ini:"FORCE_TRUST_SERVER_CERT"`
+	UseClientCert        bool   `ini:"USE_CLIENT_CERT"`
+	ClientCertFile       string `ini:"CLIENT_CERT_FILE"`
+	ClientKeyFile        string `ini:"CLIENT_KEY_FILE"`
 
 	// Sendmail sender
-	SendmailPath        string
-	SendmailArgs        []string
-	SendmailTimeout     time.Duration
-	SendmailConvertCRLF bool
+	SendmailPath        string        `ini:"SENDMAIL_PATH"`
+	SendmailArgs        []string      `ini:"-"`
+	SendmailTimeout     time.Duration `ini:"SENDMAIL_TIMEOUT"`
+	SendmailConvertCRLF bool          `ini:"SENDMAIL_CONVERT_CRLF"`
 }
 
 // MailService the global mailer
@@ -56,35 +57,12 @@ func newMailService() {
 		return
 	}
 
-	MailService = &Mailer{
-		Name:            sec.Key("NAME").MustString(AppName),
-		SendAsPlainText: sec.Key("SEND_AS_PLAIN_TEXT").MustBool(false),
-
-		Protocol:             sec.Key("PROTOCOL").In("", []string{"smtp", "smtps", "smtp+startls", "smtp+unix", "sendmail", "dummy"}),
-		SMTPAddr:             sec.Key("SMTP_ADDR").String(),
-		SMTPPort:             sec.Key("SMTP_PORT").String(),
-		User:                 sec.Key("USER").String(),
-		Passwd:               sec.Key("PASSWD").String(),
-		EnableHelo:           sec.Key("ENABLE_HELO").MustBool(true),
-		HeloHostname:         sec.Key("HELO_HOSTNAME").String(),
-		ForceTrustServerCert: sec.Key("FORCE_TRUST_SERVER_CERT").MustBool(false),
-		UseClientCert:        sec.Key("USE_CLIENT_CERT").MustBool(false),
-		ClientCertFile:       sec.Key("CLIENT_CERT_FILE").String(),
-		ClientKeyFile:        sec.Key("CLIENT_KEY_FILE").String(),
-		SubjectPrefix:        sec.Key("SUBJECT_PREFIX").MustString(""),
-
-		SendmailPath:        sec.Key("SENDMAIL_PATH").MustString("sendmail"),
-		SendmailTimeout:     sec.Key("SENDMAIL_TIMEOUT").MustDuration(5 * time.Minute),
-		SendmailConvertCRLF: sec.Key("SENDMAIL_CONVERT_CRLF").MustBool(true),
-	}
-	MailService.From = sec.Key("FROM").MustString(MailService.User)
-	MailService.EnvelopeFrom = sec.Key("ENVELOPE_FROM").MustString("")
-
+	// Handle Deprecations and map on to new configuration
 	// FIXME: DEPRECATED to be removed in v1.19.0
 	deprecatedSetting("mailer", "MAILER_TYPE", "mailer", "PROTOCOL")
 	if sec.HasKey("MAILER_TYPE") && !sec.HasKey("PROTOCOL") {
 		if sec.Key("MAILER_TYPE").String() == "sendmail" {
-			MailService.Protocol = "sendmail"
+			sec.Key("PROTOCOL").MustString("sendmail")
 		}
 	}
 
@@ -96,31 +74,91 @@ func newMailService() {
 		if err != nil {
 			log.Fatal("Invalid mailer.HOST (%s): %v", givenHost, err)
 		}
-		MailService.SMTPAddr = addr
-		MailService.SMTPPort = port
+		sec.Key("SMTP_ADDR").MustString(addr)
+		sec.Key("SMTP_PORT").MustString(port)
 	}
 
 	// FIXME: DEPRECATED to be removed in v1.19.0
 	deprecatedSetting("mailer", "IS_TLS_ENABLED", "mailer", "PROTOCOL")
 	if sec.HasKey("IS_TLS_ENABLED") && !sec.HasKey("PROTOCOL") {
 		if sec.Key("IS_TLS_ENABLED").MustBool() {
-			MailService.Protocol = "smtps"
+			sec.Key("PROTOCOL").MustString("smtps")
 		} else {
-			MailService.Protocol = "smtp+startls"
+			sec.Key("PROTOCOL").MustString("smtp+starttls")
 		}
 	}
 
+	// FIXME: DEPRECATED to be removed in v1.19.0
+	deprecatedSetting("mailer", "DISABLE_HELO", "mailer", "ENABLE_HELO")
+	if sec.HasKey("DISABLE_HELO") && !sec.HasKey("ENABLE_HELO") {
+		sec.Key("ENABLE_HELO").MustBool(!sec.Key("DISABLE_HELO").MustBool())
+	}
+
+	// FIXME: DEPRECATED to be removed in v1.19.0
+	deprecatedSetting("mailer", "SKIP_VERIFY", "mailer", "FORCE_TRUST_SERVER_CERT")
+	if sec.HasKey("SKIP_VERIFY") && !sec.HasKey("FORCE_TRUST_SERVER_CERT") {
+		sec.Key("FORCE_TRUST_SERVER_CERT").MustBool(sec.Key("SKIP_VERIFY").MustBool())
+	}
+
+	// FIXME: DEPRECATED to be removed in v1.19.0
+	deprecatedSetting("mailer", "USE_CERTIFICATE", "mailer", "USE_CLIENT_CERT")
+	if sec.HasKey("USE_CERTIFICATE") && !sec.HasKey("USE_CLIENT_CERT") {
+		sec.Key("USE_CLIENT_CERT").MustBool(sec.Key("USE_CERTIFICATE").MustBool())
+	}
+
+	// FIXME: DEPRECATED to be removed in v1.19.0
+	deprecatedSetting("mailer", "CERT_FILE", "mailer", "CLIENT_CERT_FILE")
+	if sec.HasKey("CERT_FILE") && !sec.HasKey("CLIENT_CERT_FILE") {
+		sec.Key("CERT_FILE").MustString(sec.Key("CERT_FILE").String())
+	}
+
+	// FIXME: DEPRECATED to be removed in v1.19.0
+	deprecatedSetting("mailer", "KEY_FILE", "mailer", "CLIENT_KEY_FILE")
+	if sec.HasKey("KEY_FILE") && !sec.HasKey("CLIENT_KEY_FILE") {
+		sec.Key("KEY_FILE").MustString(sec.Key("KEY_FILE").String())
+	}
+
+	// FIXME: DEPRECATED to be removed in v1.19.0
+	deprecatedSetting("mailer", "ENABLE_HTML_ALTERNATIVE", "mailer", "SEND_AS_PLAIN_TEXT")
+	if sec.HasKey("ENABLE_HTML_ALTERNATIVE") && !sec.HasKey("SEND_AS_PLAIN_TEXT") {
+		sec.Key("SEND_AS_PLAIN_TEXT").MustBool(!sec.Key("ENABLE_HTML_ALTERNATIVE").MustBool(false))
+	}
+
+	if sec.HasKey("PROTOCOL") && sec.Key("PROTOCOL").String() == "smtp+startls" {
+		log.Error("Deprecated fallback `[mailer]` `PROTOCOL = smtp+startls` present. Use `[mailer]` `PROTOCOL = smtp+starttls`` instead. This fallback will be removed in v1.19.0")
+		sec.Key("PROTOCOL").SetValue("smtp+starttls")
+	}
+
+	// Set default values & validate
+	sec.Key("NAME").MustString(AppName)
+	sec.Key("PROTOCOL").In("", []string{"smtp", "smtps", "smtp+starttls", "smtp+unix", "sendmail", "dummy"})
+	sec.Key("ENABLE_HELO").MustBool(true)
+	sec.Key("FORCE_TRUST_SERVER_CERT").MustBool(false)
+	sec.Key("USE_CLIENT_CERT").MustBool(false)
+	sec.Key("SENDMAIL_PATH").MustString("sendmail")
+	sec.Key("SENDMAIL_TIMEOUT").MustDuration(5 * time.Minute)
+	sec.Key("SENDMAIL_CONVERT_CRLF").MustBool(true)
+	sec.Key("FROM").MustString(sec.Key("USER").String())
+
+	// Now map the values on to the MailService
+	MailService = &Mailer{}
+	if err := sec.MapTo(MailService); err != nil {
+		log.Fatal("Unable to map [mailer] section on to MailService. Error: %v", err)
+	}
+
+	// Infer SMTPPort if not set
 	if MailService.SMTPPort == "" {
 		switch MailService.Protocol {
 		case "smtp":
 			MailService.SMTPPort = "25"
 		case "smtps":
 			MailService.SMTPPort = "465"
-		case "smtp+startls":
+		case "smtp+starttls":
 			MailService.SMTPPort = "587"
 		}
 	}
 
+	// Infer Protocol
 	if MailService.Protocol == "" {
 		if strings.ContainsAny(MailService.SMTPAddr, "/\\") {
 			MailService.Protocol = "smtp+unix"
@@ -131,7 +169,7 @@ func newMailService() {
 			case "465":
 				MailService.Protocol = "smtps"
 			case "587":
-				MailService.Protocol = "smtp+startls"
+				MailService.Protocol = "smtp+starttls"
 			default:
 				log.Error("unable to infer unspecified mailer.PROTOCOL from mailer.SMTP_PORT = %q, assume using smtps", MailService.SMTPPort)
 				MailService.Protocol = "smtps"
@@ -151,42 +189,6 @@ func newMailService() {
 		}
 	}
 
-	// FIXME: DEPRECATED to be removed in v1.19.0
-	deprecatedSetting("mailer", "DISABLE_HELO", "mailer", "ENABLE_HELO")
-	if sec.HasKey("DISABLE_HELO") && !sec.HasKey("ENABLE_HELO") {
-		MailService.EnableHelo = !sec.Key("DISABLE_HELO").MustBool()
-	}
-
-	// FIXME: DEPRECATED to be removed in v1.19.0
-	deprecatedSetting("mailer", "SKIP_VERIFY", "mailer", "FORCE_TRUST_SERVER_CERT")
-	if sec.HasKey("SKIP_VERIFY") && !sec.HasKey("FORCE_TRUST_SERVER_CERT") {
-		MailService.ForceTrustServerCert = sec.Key("SKIP_VERIFY").MustBool()
-	}
-
-	// FIXME: DEPRECATED to be removed in v1.19.0
-	deprecatedSetting("mailer", "USE_CERTIFICATE", "mailer", "USE_CLIENT_CERT")
-	if sec.HasKey("USE_CERTIFICATE") && !sec.HasKey("USE_CLIENT_CERT") {
-		MailService.UseClientCert = sec.Key("USE_CLIENT_CERT").MustBool()
-	}
-
-	// FIXME: DEPRECATED to be removed in v1.19.0
-	deprecatedSetting("mailer", "CERT_FILE", "mailer", "CLIENT_CERT_FILE")
-	if sec.HasKey("CERT_FILE") && !sec.HasKey("CLIENT_CERT_FILE") {
-		MailService.ClientCertFile = sec.Key("CERT_FILE").String()
-	}
-
-	// FIXME: DEPRECATED to be removed in v1.19.0
-	deprecatedSetting("mailer", "KEY_FILE", "mailer", "CLIENT_KEY_FILE")
-	if sec.HasKey("KEY_FILE") && !sec.HasKey("CLIENT_KEY_FILE") {
-		MailService.ClientKeyFile = sec.Key("KEY_FILE").String()
-	}
-
-	// FIXME: DEPRECATED to be removed in v1.19.0
-	deprecatedSetting("mailer", "ENABLE_HTML_ALTERNATIVE", "mailer", "SEND_AS_PLAIN_TEXT")
-	if sec.HasKey("ENABLE_HTML_ALTERNATIVE") && !sec.HasKey("SEND_AS_PLAIN_TEXT") {
-		MailService.SendAsPlainText = !sec.Key("ENABLE_HTML_ALTERNATIVE").MustBool(false)
-	}
-
 	if MailService.From != "" {
 		parsed, err := mail.ParseAddress(MailService.From)
 		if err != nil {
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index fb425c8717..df7310b09b 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -605,7 +605,7 @@ func LoadForTest(extraConfigs ...string) {
 
 func deprecatedSetting(oldSection, oldKey, newSection, newKey string) {
 	if Cfg.Section(oldSection).HasKey(oldKey) {
-		log.Error("Deprecated fallback `[%s]` `%s` present. Use `[%s]` `%s` instead. This fallback will be removed in v1.18.0", oldSection, oldKey, newSection, newKey)
+		log.Error("Deprecated fallback `[%s]` `%s` present. Use `[%s]` `%s` instead. This fallback will be removed in v1.19.0", oldSection, oldKey, newSection, newKey)
 	}
 }
 
diff --git a/services/mailer/mailer.go b/services/mailer/mailer.go
index 46b0c8e2f4..2663b6b2ba 100644
--- a/services/mailer/mailer.go
+++ b/services/mailer/mailer.go
@@ -166,7 +166,7 @@ func (s *smtpSender) Send(from string, to []string, msg io.WriterTo) error {
 	defer conn.Close()
 
 	var tlsconfig *tls.Config
-	if opts.Protocol == "smtps" || opts.Protocol == "smtp+startls" {
+	if opts.Protocol == "smtps" || opts.Protocol == "smtp+starttls" {
 		tlsconfig = &tls.Config{
 			InsecureSkipVerify: opts.ForceTrustServerCert,
 			ServerName:         opts.SMTPAddr,
@@ -208,7 +208,7 @@ func (s *smtpSender) Send(from string, to []string, msg io.WriterTo) error {
 		}
 	}
 
-	if opts.Protocol == "smtp+startls" {
+	if opts.Protocol == "smtp+starttls" {
 		hasStartTLS, _ := client.Extension("STARTTLS")
 		if hasStartTLS {
 			if err = client.StartTLS(tlsconfig); err != nil {